I know there's an old thread similar to this one but I'm hoping to get some advice on my carb. I have an Eddy Performer 750 cfm with electric choke. It has the original jets both primary and secondary. I changed the metering rod and the spring however. Went with a rod that keeps the cruise mixture the same but makes the power one stage richer. I guess it had the orange spring in it and I changed it to the silver spring to make the power stage come in sooner. I have the original pump shooter with the setting at the top (I think) hole.
It generally runs OK but does have some issues. When the engine is cold, it kind of sputters a little at light throttle. Sometimes it backfires! It also kind of surges at steady speeds leading both my mechanic and I too think the cruise setting may be too lean. I tried the metering rod that was one stage rich both cruise and power. Although it didn't surge, mileage was terrible (bout 8 -9 mpg) and performance was no better than with the stock metering rod.
I have two calibration kits (for both Performer and Thunder carbs) and I have the entire set of pump shooters.
Couple of questions: Which hole is the top hole in the accel pump rod? The one nearest the carb (where its set now). I know the springs bring the metering rod up to the power stage at certain vacuum readings. It had the orange spring in the carb stock....Edelbrock says it stages at 4 or 5 inches of mercury. Isn't that when the throttle is almost floored?? My car has a vacuum guage. That's why I put the silver spring in. Supposedly stages about 8" of Hg. Is the vacuum reading given by Eddy when the spring starts to release or is fully released?? Which spring should I use?
Sorry bout the lack of specific part numbers. My Eddy books are downstairs and someone is sleeping and I don't want to disturb.
Ok, my car is a 67 300, stock 440 TNT with electronic ignition conversion and TTI exhaust. Its and automatic with 3.55 rear gears
I've tried quite a few carbs on my car; when I got it it had a dual quad setup with two Carter carbs. The primary carb went bad so I had it replaced with a Edelbrock Performer 600 cfm. This carb performed well but the dual quad set up was messed up. It was dealer installed when the original owners bought the car. The dealership made the FRONT carb the primary and the rear the secondary. This made the linkage and everything kind of funky and never worked quite right.
SOOO, I changed to an Eddy Thunder (800 cfm) carb with electric choke on an Eddy Performer single 4 bbl manifold. This setup gave me generally outstanding performance BUT had some issues. Fuel economy went south to the tune of 7 - 8 mpg, there was a Terrible off idle bog I couldn't get rid of and there were serious drivability issues when the temp was over 65 degrees. It was as if the fuel was boiling away from the jets...surging and all that. Then when the car was parked, it absolutely reeked of fuel.
So I sold that carb and put the Eddy 600 cfm in its place. For the most part the car performed fairly well. There were NO drivability issues, no choke issues and mileage was pretty good.....BUT, I wanted the performance the 800 cfm Thunder car gave.
I switched to a rebuilt ThermoQuad 850cfm. It was OK as far as performance was concerned but not like the 800 cfm Thunder carb. Fuel economy was like the 600 cfm Eddy. BUT there were some issues. The carb leaked fuel around the throttle plates and smelled like burning plastic. I guess the throttle return spring was not strong enough so whenever I floored it, It would stay in 4 bbl mode and not return to normal.
About 3 years ago I switched to my current setup. A 750 cfm Eddy Performer with electric choke. I was hoping to get back some of the performance from the 800 Eddy Thunder carb without trashing the fuel mileage along with getting the good drivability/reliability of the 600 cfm Performer carb.
NOT! I've had problems with the choke from day one and have Never been able to set it right. Performance is lack luster and economy is about where it was with the 600 Performer....Guess the rest of my info on this carb is in the original post....
So I sold that carb and put the Eddy 600 cfm in its place. For the most part the car performed fairly well. There were NO drivability issues, no choke issues and mileage was pretty good...